Liquid crystal composition and liquid crystal display device

ABSTRACT

Liquid crystal compositions are provided which have a particularly excellent miscibility at low temperatures, properly large Δn, and small Vth and viscosity while satisfying several characteristics required of liquid crystal composition for AM-LCD. 
     Disclosed are liquid crystal compositions containing, as a first component, at least one compound expressed by general formula either (I-1) or (I-2), and containing, as a second component, at least one compound expressed by any one of general formulas (II-1) to (II-7) ##STR1## wherein n is an integer of 1 to 10, Z 1  represents --CH 2  CH 2  -- or single bond, X represents F or OCF 3 , Y represents H or F, and m is 0 or 1. 
     The liquid crystal compositions of the present invention are useful as liquid crystal material for low voltage in several modes such as active matrix mode and STN mode.

This application is a 371 of PCT/JP 95/0401, filed Oct. 13, 1995.

This application is a 371 of PCT/JP 95/0401, filed Oct. 13, 1995,published as WO96/11995 Apr. 25, 1996.

TECHNICAL FIELD

The present invention relates to a nematic liquid crystal compositionand a liquid crystal display device using the liquid crystalcomposition. More specifically, the present invention relates to aliquid crystal composition for active matrix liquid crystal displaydevice and a liquid crystal display device using the composition.

BACKGROUND ART

Since liquid crystal display device (LCD) can reduce its electric powerconsumption and can downsize its shape compared with CRT (cathode raytube display), several types of LCDs such as twist nematic (TN) mode,super twist nematic (STN) mode, and thin-film transistor (TFT) mode LCDshave practically been used. Among them, active matrix LCD (AM-LCD) suchas thin-film transistor (TFT) has been progressed in actualization ofcolored display and of fine picture image, and thus the AM-LCD hasattracted public attention.

As the characteristics required of liquid crystal composition forAM-LCD, the following can be mentioned:

1) Voltage holding ratio (V.H.R) is high to maintain a high contrast ofLCD.

2) Range of nematic liquid crystal phase is wide depending onapplication environment.

3) Appropriate optical anisotropy (Δn) can be produced depending on cellthickness.

4) Proper threshold voltage can be obtained depending on drivingcircuit.

5) Speed of electrooptical response is high to cope with dynamic image.

As driving mode of AM-LCD, the TN display mode is adopted in which thealignment of liquid crystal molecules placed between an upper and lowersubstrates are twisted by 90°. In this TN display mode, the product(Δn·d) of optical anisotropy (Δn) and cell thickness (d) μm must beestablished to a certain value (for example, Δn·d˜0.5 μm) to prevent thecoloring of the background of the liquid crystal cell due to theinterference of liquid crystal cells when voltage is not applied and toobtain a best contrast.

Under these restrictions, the value of about 0.07 to about 0.11,particularly about 0.08 to about 0.10 has become a main Δn of the liquidcrystal composition currently in practical use for TFT for the devicewhich employs a light transmittance of about first minimum value.

Also, the development of LCD with a purpose of coping with dynamicpicture came to be strongly sought in recent years. Since the responsespeed (τ) is proportional to the viscosity (η) of liquid crystalmaterial, the development of liquid crystal composition having a lowviscosity has come to be sought.

Further, with the development of portable LCD, the development on theassumption of using it outdoors has come to be studied. In order towithstand outdoor use, it is required to exhibit nematic phase over arange beyond the temperature range of application environment. Fromthese viewpoints, liquid crystal compositions having a nematic-isotropicphase transition temperature (clearing point: TNI) of higher than 60° C.and smectic-nematic phase transition temperature (TSN) of lower than-20° C. have become main liquid crystal compositions currently inpractical use for TFT.

With such background, trifluoro compounds having a comparatively largedielectric anisotropy (Δε) are disclosed in Japanese Patent ApplicationLaid-open No. Hei 2-233626. Whereas a composition comprising 15% byweight of a trifluoro compound and 85% by weight of a difluoro compoundis disclosed as an example in its Application Example 2, the compositionhas the defect of being short of practicability since its thresholdvoltage is high, miscibility is poor at low temperatures in particular,and nematic phase range is narrow. Besides, the composition has a defectof having a high viscosity.

In WO 94/03558 publication, examples of compositions comprising atrifluoro compound and a difluoro compound are disclosed. However, thecompositions disclosed in its Examples 1 and 2 are as low as 50° C. orlower in clearing point, and less than 0.06 in Δn; and thus they areshort of utility. Besides, the compositions disclosed in and afterExample 4 have a defect of having a high threshold voltage.

Whereas liquid crystal compositions are diligently being studieddepending on several purposes as mentioned above, it is a presentsituation that new improvements are all the time demanded.

DISCLOSURE OF THE INVENTION

An object of the present invention is particularly to provide a liquidcrystal composition having an excellent miscibility at low temperatures,a properly large Δn, and a small Vth and viscosity, while satisfyingseveral characteristics required of AM-LCD mentioned above.

As a result of the research by the present inventors on the liquidcrystal compositions which used several liquid crystal compounds, tosolve such problems, it has been found that the object can be achievedby the liquid crystal compositions of the present invention.

Specifically speaking, physical properties of novel difluorooxymethanederivatives which can be derived from phenylbenzoate derivatives hadbeen investigated by the present inventors to find i) that the directionof dipole moment by the polarization of two fluorine atoms indifluoromethoxy group, which is a bonding group, efficiently contributesto the increase of dielectric constant in the direction of major axis ofthe molecule in the difluorooxymethane derivative and produces a largedielectric anisotropy, and thus it is effective for lowering thresholdvoltage; and ii) that the derivatives are extremely low in viscosity.

Also, it had been found that the compounds in which fluorine containinggroup is selected as their terminal substituent are novel liquidcrystalline compounds for low voltage useful in AM-LCD.

As a result of diligent investigation on the compositions containingsuch liquid crystal compounds, it has now been found that the problemsmentioned above can be solved when the liquid crystal compositions ofthe present invention are used for AM-LCD; and thus the presentinvention is described in detail below.

The present invention is concerned with a liquid crystal compositioncontaining at least one specific difluorooxymethane derivative expressedby general formula (I) ##STR2## wherein l is 1, m is 0, n is 0 or 1,ring A₁ represents trans-1,4-cyclohexylene group, ring A₃ represents1,4-phenylene group, Z₁ represents --CH₂ CH₂ -- or a covalent bond, Z₂and Z₃ represent a covalent bond, L₁ and L₂ represent hydrogen atom, L₃represents hydrogen atom, L₄ represents Y (Y indicates hydrogen atom orfluorine atom), R represents an alkyl group expressed by C_(n) H_(2n+1)(n indicates an integer of 1 to 10), and X represents fluorine atom orOCF₃ ; said specific difluorooxymethane derivative being included in thecompounds expressed by the same general formula (I) mentioned abovewherein each of l, m, and n is 0 or 1, rings A₁ and A₂ independentlyrepresent trans-1,4-cyclohexylene group, 1,4-phenylene group one or morehydrogen atoms in which six-membered ring may be replaced by halogenatom, trans-1,3-dioxane-2,5-diyl, or pyrimidine-2,5-diyl, ring A₃represents 1,4-phenylene group one or more hydrogen atoms in whichsix-membered ring may be replaced by halogen atom,trans-1,3-dioxane-2,5-diyl, or pyrimidine-2,5-diyl, Z₁, Z₂, and Z₃independently represent a covalent bond, --CH₂ CH₂ --, --COO--, --CF₂O--, --OCF₂ --, --CH₂ O--, --OCH₂ --, --CH═CH--, or --C.tbd.C--, L₁, L₂,L₃, and L₄ independently represent hydrogen atom or halogen atom,respectively, X is halogen atom, CN, CF₃, OCF₃, OCHF₂, OCH₂ F, or alinear or branched alkyl group, alkenyl group, or alkoxy group having 1to 10 carbon atoms, and R is a linear or branched alkyl group or alkenylgroup having 1 to 10 carbon atoms, one or not adjacent 2 or more CH₂groups in the R may be replaced by oxygen atom, provided that in no caseX is an alkyl group, alkenyl group, or alkoxy group except in the casewhere Z₂ is --CF₂ O-- or --OCF₂ --.

That is, the first aspect of the present invention is concerned with aliquid crystal composition characterized by containing, as a firstcomponent, at least one compound expressed by either general formula(I-1) or (I-2) and containing, as a second component, at least onecompound expressed by any one of general formulas (II-1) to (II-7).##STR3## wherein n is an integer of 1 to 10, Z¹ represents --CH₂ CH₂ --or single bond, X represents F or OCF₃, and Y represents H or F, and mis 0 or 1.

Second aspect of the present invention is concerned with the liquidcrystal composition recited in the first aspect of the present inventioncharacterized in that the amount of the first component is 3 to 40% byweight and that of the second component is 60 to 97% by weight eachbased on the total weight of the liquid crystal composition.

Third aspect of the present invention is concerned with the liquidcrystal composition characterized by further containing a compoundexpressed by general formula (III) in addition to the liquid crystalcomposition recited in the first or the second aspect of the presentinvention mentioned above ##STR4## wherein n is an integer of 1 to 10, Xrepresents F or OCF₃, Y represents F or H, and Z² represents --CH₂ CH₂-- or single bond.

Fourth aspect of the present invention is concerned with the liquidcrystal composition characterized by containing a compound expressed bygeneral formula (IV-1) and/or (IV-2) in addition to the liquid crystalcomposition recited in any one of the first to third aspect of thepresent invention mentioned above. ##STR5##

Fifth aspect of the present invention is concerned with the liquidcrystal composition characterized by containing at least one compoundexpressed by any one of general formulas (V-1) to (V-3) in addition tothe liquid crystal composition recited in any one of the first to thirdaspect of the present invention mentioned above ##STR6## wherein R¹, R³,and R⁵ represent an alkyl group or alkenyl group having 1 to 10 carbonatoms; in any of R¹, R³, and R⁵, any one or not adjacent two methylene(--CH₂ --) groups may replaced by oxygen (--O--) atom; R², R⁴, and R⁶represent an alkyl group or alkoxy group having 1 to 10 carbon atoms, Arepresents trans-1,4-cyclohexylene group or 1,4-phenylene group, Z³represents --CH═CH-- or --C.tbd.C--, Y represents H or F, and p is 0 or1.

Sixth aspect of the present invention is concerned with the liquidcrystal display device which has used a liquid crystal compositionrecited in any one of the first to fifth aspect of the present inventionmentioned above.

BEST MODE FOR CARRYING OUT THE INVENTION

Compounds composing each component in the present invention areexplained below.

In the present invention, the following compounds are preferable as theones expressed by general formula (I-1) or (I-2): ##STR7##

Compounds of general formula (I-1) assume the role particularly ofmaintaining the threshold voltage and reducing the viscosity of liquidcrystal compositions for TFT since they have a value of dielectricanisotropy (Δε) in a range of about 6 to about 11 and a low viscosityfor their values of Δε, and are excellent in thermal and chemicalstability.

Compounds of general formula (I-2) assume the role of lowering thethreshold voltage as well as the role of raising the clearing point ofliquid crystal compositions since they are tetracyclic compounds.

Amount of the first component to be used in the present invention ispreferably 3 to 40% by weight, and more desirably 5 to 35% by weight.When it is less than 3% by weight, the effect of low voltage, which is aprincipal subject of the present invention, is hardly obtained. When itexceeds 40% by weight, the miscibility of liquid crystal compositionsbecomes poor at low temperatures in some instances.

Compounds of general formulas (I-1) and (I-2) can be prepared by theprocedures as follows:

First, a method for preparing a difluorooxymethane derivative expressedby general formula (I) is illustrated.

As shown in equation 1 below, a benzonitrile derivative, which isexpressed by general formula (A) and used as raw material for thepreparation, is hydrolyzed in an alcohol solvent such as ethyl alcohol,ethylene glycol, and diethylene glycol by using, as catalyst, a basesuch as sodium hydroxide and potassium hydroxide, or a mineral acid suchas hydrochloric acid and sulfuric acid, to lead to a carboxylic acidderivative (B). Then, the carboxylic acid derivative (B) is reacted witha phenol derivative expressed by general formula (C) according to ageneral esterification method, for instance, by using, as acid catalyst,a mineral acid such as hydrochloric acid and sulfuric acid, an organicacid such as p-toluene sulfonic acid, or an ion exchange resin such asAmberite, or by using N,N'-dicyclohexyl-carbodiimide (DCC) as catalyst,to prepare an ester derivative expressed by general formula (D). Also,the derivative (D) can be prepared by reacting (B) with thionyl chlorideto convert into an acid chloride and then reacting with the (C) in thepresence of a base such as pyridine. Subsequently, the ester derivative(D) is reacted with Lawesson reagent,2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane-2,4-disulfide!(Bull. Soc. Chim. Belg., 87, 223, 229, 299, 525 (1978); Synthesis, 941(1979); Tetrahedron, 35, 2433 (1979); Tetrahedron, Lett., 21, 4061(1980)) by using benzene or toluene as solvent at an optionaltemperature from room temperature to the boiling point of the solvent tolead to a thioester (thione type) derivative (E). Then, the thioesterderivative (thione type) (E) is reacted with diethylaminosulfurtrifluoride (DAST) (Synthesis, 787 (1973)) by using dichloromethane orchloroform as solvent at an optional temperature from room temperatureto the boiling point of the solvent for conducting gem-fluorination toprepare an objective difluorooxymethane derivative. ##STR8##

As an alternative method, as shown in equation 2 below, adifluorooxymethane derivative can be prepared by first preparingGrignard reagent from a bromobenzene derivative (F), reacting it withcarbon disulfide to form a dithiocarboxylic acid derivative (G),converting it with thionyl chloride into thiocarboxylic acid chloride,reacting with a phenol derivative (C) to prepare a thioester (thionetype) derivative (E), and then reacting with DAST in the same way asmentioned above. ##STR9##

Among the compounds expressed by the general formula (I), compound (7),which is an analogue of the compounds expressed by general formula (I-1)or (I-2) and a first component in the present invention can be preparedby the method as shown in equation 3 below:

Alkylbenzoic acid derivative 1 is first subjected to an esterificationwith 3,4-difluorophenol according to a general esterification method,for instance, by using, as acid catalyst, a mineral acid such ashydrochloric acid and sulfuric acid, an organic acid such as p-toluenesulfonic acid, or an ion exchange resin such as Amberite, or by usingN,N'-dicyclohexyl-carbodiimide (DCC) as catalyst to prepare3,4-difluorobenzoate derivative 2. Subsequently, the derivative 2 isreacted with Lawesson reagent under toluene refluxing condition toconvert into a thioester (thione type) derivative 3, and then reactedwith DAST in dichloromethane to prepare compound (7). Besides, compoundsexpressed by general formula (I-1) or (I-2) can be prepared from severalkinds of known benzoic acid derivatives according to the preparationprocedures mentioned above and by using a phenol having a different kindof substituent in place of 3,4-difluorophenol. ##STR10##

In this connection, 3,4-difluorophenol, which is a raw material for thepreparation, can be prepared by using 3,4-difluorobromobenzene asstarting material. That is, as shown in equation 4 below, it can beprepared by reacting Grignard reagent prepared from3,4-difluorobromobenzene with t-butyl hydroperoxide according to themethod of S. O. Lawesson et al. (J. Am. Chem. Soc. 81, 4230 (1959)) orby treating Grignard reagent prepared from 3,4-difluorobromobenzene withtrialkyl borate according to the method of R. L. Kidwell et al. (Org.Synth., V, 918, (1973)) to convert into a boric acid ester and thensubjecting to an oxidizing treatment with hydrogen peroxide solution.##STR11##

Among the compounds expressed by general formula (I-1), for example,compound (I-1-3) can be prepared by the method as shown in equation 5below:

First, 4-(trans-4-alkylcyclohexyl)benzonitrile 4 is hydrolyzed inethylene glycol or diethylene glycol in the presence of sodium hydroxideto convert into a benzoic acid derivative 5, subjected to anesterification with 3,4-difluoro-phenol according to a generalesterification method, for instance, by using, as acid catalyst, amineral acid such as hydrochloric acid and sulfuric acid, an organicacid such as p-toluene sulfonic acid, or an ion exchange resin such asAmberite, or by using N,N'-dicyclohexylcarbodiimide (DCC) as catalyst toprepare phenylbenzoate derivative 6. Subsequently, the derivative 6 isreacted with Lawesson reagent under toluene refluxing condition toconvert into a thioester (thione type) derivative 7, and then reactedwith DAST in dichloromethane to prepare compound (I-1-3). Besides,compounds (I-1-1) to (I-1- 2), and (I-1-4) can be prepared from severalkinds of known benzoic acid derivatives according to the preparationprocedures mentioned above and by using phenol having a different kindof substituent in place of 3,4-difluorophenol. ##STR12##

As shown in equation 6 below, for example, compound (I-2-3) among thecompounds expressed by general formula (I-2) can be prepared by thefollowing method:

That is, iodobenzene is subjected to a coupling reaction with Grignardreagent prepared from 3,4-difluorobromobenzene, in the presence of anovel metal catalyst such as palladium chloride to convert into abiphenyl derivative 8 and then reacted with bromine in the presence ofmetal powder such as iron powder to prepare a bromobiphenyl derivative9. Subsequently, Grignard reagent prepared from the derivative 9 isreacted with trimethyl borate according to the report by R. L. Kidwellet al. (Org. Synth., V, 918 (1973)), and then oxidized with hydrogenperoxide in the presence of acetic acid to prepare a phenyl phenolderivative 10. Compound (I-2-3) can be prepared by treating thederivative 10 in the same way as in the case of the preparation ofcompound (7). Further, the compounds (I-2-1) to (I-2-2), and (I-2-4) canbe prepared from phenyl phenol derivatives which were prepared by usingbromobenzene derivatives having a different kind of substituent in placeof 3,4-difulorobromobenzene. ##STR13##

Among the compounds expressed by general formula (I-1) or (I-2), thecompounds indicated by the formula wherein Z¹ is --CH₂ CH₂ -- can beprepared by the methods as shown in equation 7 below:

First, 4- 2-(trans-4-alkylcyclohexyl)ethyl!benzoic acid as raw materialfor the preparation can be prepared by hydrolyzing a known compound, 4-2-(trans-4-alkylcyclohexyl)ethyl! benzonitrile in ethylene glycol ordiethylene glycol in the presence of sodium hydroxide. From the benzoicacid derivative and one of several phenol derivatives, a phenyl benzoatederivative can be prepared according to the esterification method asmentioned above. Compounds (I-1-5) to (I-1-8), and (I-2-5) to (I-2-8)can be prepared by treating the phenylbenzoate derivative with Lawessonreagent in the same way as mentioned above to convert into a thioester(thione type) and then reacting with DAST. ##STR14##

As the compounds expressed by general formulas (II-1) to (II-7) in thepresent invention, the following compounds are preferable: ##STR15##wherein n is an integer of 1 to 10.

Among theses compounds, the compounds of formula (II-1-1), (II-1-2),(II-1-3), (II-2-2), (II-3-1), (II-3-2), (II-3-3), (II-4-1), (II-4-2),(II-5-2), (II-6-1), (II-6-4), and (II-7-1) are particularly preferable.

Since the compounds of general formula (II) have a Δε in a range ofabout 5 to about 8 and are excellent in thermal and chemical stability,they are well known compounds as ones for TFT.

Compounds of general formula (II) have a nematic-isotropic phasetransition point (clearing point: TNI) in a range of about 90 to 130° C.and are best ones as base compound of liquid crystal composition for lowvoltage TFT.

Amount of the second component in the present invention is preferably 60to 97% by weight, and more desirably 65 to 95% by weight. When theamount is less than 60% by weight, the miscibility of the liquid crystalcomposition becomes unfavorably poor at low temperatures in someinstances. When the amount exceeds 97% by weight, the effect of lowvoltage of the present invention is hardly obtained.

In the present invention, the following compounds are preferable as onesexpressed by general formula (III): ##STR16## wherein n is an integer of1 to 10.

Among these compounds, the compounds of formula (III-1), (III-2), and(III-5) are particularly preferable.

Since the compounds of general formula (III) are bicyclic compounds,they assume the role of lowering the threshold voltage of liquid crystalcompositions, in particular. Since they are bicyclic compounds, whenthey are used in a large amount, the clearing point of liquid crystalcomposition is lowered in some instances. Amount of the compounds ofgeneral formula (III) to be used is preferably less than 15% by weight.

Compounds of general formula (IV) are bicyclic or tricyclic chlorinecontaining compounds. These compounds assume the role of primarilyreducing the viscosity of liquid crystal composition. Since their Δε isas low as 4 to 5, when they are used in a large amount, the thresholdvoltage of liquid crystal composition becomes high in some instances.Amount of the compounds of general formula (IV) is preferably less than35% by weight.

In the present invention, the following compounds are preferable as onesexpressed by general formula (V): ##STR17## wherein R and R'independently represent an alkyl group or alkenyl group.

Among these compounds, the compounds expressed by formula (V-1-1),(V-1-2), (V-1-3), (V-1-5), (V-1-6), (V-1-7), (V-2-2), (V-2-4), (V-3-1),(V-3-2), (V-3-3) are particularly preferable.

Compounds of general formula (V) are bicyclic to tetracyclic compoundshaving a negative or small positive dielectric anisotropy. Among these,the compounds of bicyclic or tricyclic compounds are used with thepurpose principally of reducing the viscosity and/or adjusting the Δn ofliquid crystal composition. Tetracyclic compounds are used with thepurpose of raising the clearing point to expand the nematic range and/orwith the purpose of adjusting the Δn and viscosity.

Liquid crystal compositions of the present invention may contain anappropriate amount of the compounds other than those expressed by thegeneral formulas (I) to (V-3-3) mentioned above in the range in whichthe objects of the present invention is not impaired, with the purposeof adjusting the threshold voltage, nematic range, Δn, dielctricanisotropy, and viscosity.

Liquid crystal compositions of the present invention are prepared byconventional methods. Generally, the method is adopted in which variouscomponents are dissolved in each other at a high temperature. Also, theliquid crystal compositions of the present invention are improved tooptimize, depending on the applications intended, with a suitableadditive. Such additives are described in literatures. Usually, a chiraldopant or likes are added to cause a helical structure of liquid crystalto adjust a required twisting angle, and to avoid reverse-twist.

Further, the liquid crystal compositions of the present invention can beadded with a dichroic dye such as merocyanine type, styryl type, azotype, azomethine type, azoxy type, quinophthalone type, anthraquinonetype, and tetrazine type, and used as liquid crystal composition forguest-host (GH) mode. Alternatively, they can also be used as liquidcrystal compositions for polymer dispersion type liquid crystal displaydevices (PDLCD) typified by NCAP which is prepared by forming a nematicliquid crystal into a microcapsule or typified by a polymer net workliquid crystal display device (PNLCD) which is prepared by forming apolymer of three-dimensional network structure in a liquid crystal.Also, the liquid crystal compositions of the present invention can beused as ones for electrically controlled birefringence (ECB) mode ordynamic scattering (DS) mode.

The present invention will be described in more detail below withreference to Examples. However, it should be understood that the presentinvention is by no means restricted by such specific Examples.

Preparation Examples of the compounds of general formula (I-1) and (I-2)are first described which are the first component in the liquid crystalcompositions of the present invention. In each of the Examples, Crrepresents crystal, N does nematic phase, Nl does monotropic phase, Sdoes smectic phase, SB does smectic B phase, Iso represents isotropicliquid, and the unit of every phase transition temperature is °C.

COMPOUND PREPARATION EXAMPLE 1!

Preparation of difluoro-4-(trans-4-propyl-cyclohexyl)phenyl!-(3,4,5-trifluorophenyloxy)methane(An analogue of the compound of formula (I-1-1)).

In a 500 ml three neck distillation flask provided with a stirrer,thermometer, dropping funnel, and nitrogen gas introducing pipe, 15.0 g(60.9 mmol) of 4-(trans-4-propyl-cyclohexyl)benzoic acid, 15.1 g (73.1mmol) of DCC (N,N'-dicyclohexylcarbodiimide), and 0.3 g (2.2 mmol) ofDMAP (4-dimethylaminopyridine) were dissolved in 250 ml ofdichloromethane under nitrogen gas atmosphere, and then 10.8 g (73.0mmol) of 3,4,5-trifluorophenol was added dropwise to the solution in 3min while stirring at room temperature. After the dropping, the solutionwas stirred for 10 hours at room temperature. Then, 100 ml of water wasadded to the reaction solution. After dichloromethane insoluble matterwas filtered off, the dichloromethane layer was separated and the waterlayer was further extracted with 200 ml of dichloromethane. Extractedlayers were mixed and washed with 100 ml×2 of water, 100 ml of saturatedaqueous solution of sodium hydrogencarbonate, and 100 ml×2 of water inturn, dried over anhydrous magnesium sulfate, and then concentratedunder a reduced pressure to obtain 23.8 g of reaction product. Reactionproduct was purified by a column chromatography using silica gel asfiller and using toluene as developing solvent, and furtherrecrystallized from a mixed solvent of heptane-ethanol to obtain 13.2 gof colorless crystal product. This product was 3,4,5-trifluoro-4-(trans-4-propylcyclohexyl)phenyl!benzoate.

Subsequently, in a 1000 ml egg-plant type flask provided with a nitrogengas introducing pipe and cooling pipe, 13.2 g (35.2 mmol) of3,4,5-trifluoro- 4-(trans-4-propyl-cyclohexyl)phenyl!benzoate obtainedby the procedures mentioned above and 28.5 g (70.4 mmol) of Lawessonreagent(2,4-bis(4-methoxyphenyl)-1,3-dithia-2,4-diphosphethane-2,4-disulfide)were dissolved in 500 ml of toluene, and the solution was refluxed whilestirring under nitrogen gas stream for 60 hours. After the reactionsolution was cooled down to room temperature, 200 ml of water was added,the toluene layer was separated, and then the water layer was furtherextracted with 150 ml of toluene. Organic layers were mixed, washed with200 ml×2 of water, 100 ml of saturated aqueous solution of sodiumhydrogencarbonate, 100 ml of 10% aqueous solution of sodiumhydrogensulfite, and 200×2 ml of water in turn, dried over anhydrousmagnesium sulfate, and then concentrated under a reduced pressure toobtain 13.8 g of brown crystalline mixture. Reaction product waspurified by a column chromatography using silica gel as filler and usingheptane as developing solvent, and then recrystallized from heptane toobtain 4.7 g of yellow needle-like crystal product having a phasetransition point: Cr 127.7°-128.2° C. Iso. This product was4-(trans-4-propyl-cyclohexyl)phenyl carbothioacid-O-3,4,5-trifluorophenyl.

1H-NMR (CDC13; δ ppm) 0.8-2.0(16H,m), 2.57(1H,m), 6.78(2H,m),7.29(2H,d,J=8.2 Hz), and 8.23(2H,d,J=8.2 Hz).

Subsequently, in a 100 ml egg-plant type flask provided with a nitrogengas introducing pipe, 4.7 g (12.1 mmol) of4-(trans-4-propylcyclohexyl)phenyl carbothioacid-O-3,4,5-trifluorophenyl was dissolved in 50 ml of dichloromethane,and then 5.9 g (36.2 mmol) of DAST (diethylaminosulfur trifluoride) wasadded to the solution and then the solution was stirred at roomtemperature for 34 hours. Reaction solution was added with 50 ml ofwater, the dichloromethane layer was separated, and the water layer wasfurther extracted with 50 ml of dichloromethane. Extracted layers weremixed, washed with 50 ml×2 of water, 30 ml of saturated aqueous solutionof sodium hydrogencarbonate, and 50 ml×2 of water in turn, dried overanhydrous magnesium sulfate, and then concentrated under a reducedpressure to obtain 4.3 g of colorless crystal product. Reaction productwas purified by a column chromatography using silica gel as filler andusing heptane as developing solvent, and then recrystallized fromheptane to obtain 1.5 g of colorless needle-like crystal product (phasetransition point: Cr 70.5-71.4 Iso). This product was difluoro-4-(trans-4-propylcyclohexyl)phenyl!-(3,4,5-trifluoro-phenyloxy)methane.

1H-NMR (CDC13; δ ppm) 0.80-2.10(16H,m), 2.60(1H,m), 6.96(2H,m),7.32(2H,d,J=8.6 Hz), and 7.62(2H,d,J=8.6 Hz). 19F-NMR (CDC13; δ ppm)-66.754(2F,s,--CF20--), -133.521(2F,d), -164.754(1F,t).

GC-MS(CI)m/z251(100%), 379(M++1-HF,34), and 125(27).

Following compounds of formula (I-1) can be prepared according to thepreparation method mentioned above by using4-(trans-4-alkylcyclohexyl)benzoic acids having a different alkyl chainin place of 4-(trans-4-propylcycohexyl)benzoic acid and using severalknown phenol derivatives in place of 3,4,5-trifluorophenol:

Difluoro- 4-(trans-4-ethylcyclohexyl)phenyl!-(4-fluorophenyloxy) methane

Difluoro-4-(trans-4-propylcyclohexyl)phenyl!-(4-fluoro-phenyloxy)methane

Difluoro-4-(trans-4-pentylcyclohexyl)phenyl!-(4-fluoro-phenyloxy)methane

Difluoro-4-(trans-4-ethylcyclohexyl)phenyl!-(3,4-difluoro-phenyloxy)methane

Difluoro-4-(trans-4-propylcyclohexyl)phenyl!-(3,4-difluoro-phenyloxy)methane

Difluoro-4-(trans-4-pentylcyclohexyl)phenyl!-(3,4-difluoro-phenyloxy)methane

Cr 42.9-43.4 N 66.2-67.5 Iso

Difluoro-4-(trans-4-ethylcyclohexyl)phenyl!-(4-trifluoro-methoxyphenyloxy)methane

Difluoro-4-(trans-4-propylcyclohexyl)phenyl!-(4-trifluoro-methoxyphenyloxy)methane

Cr 57.3-58.2 SB 70.9-72.0 N 83.1-83.5 Iso-

Difluoro-4-(trans-4-butylcyclohexyl)phenyl!-(4-trifluoro-methoxyphenyloxy)methane

Difluoro-4-(trans-4-pentylcyclohexyl)phenyl!-(4-trifluoro-methoxyphenyloxy)methane

Cr 68.1-68.3 SB 80.5-80.8 N 90.2-90.4 Iso

Difluoro-4-(trans-4-ethylcyclohexyl)phenyl!-(3-fluoro-4-trifluoromethoxyphenyloxy)methane

Difluoro-4-(trans-4-propylcyclohexyl)phenyl!-(3-fluoro-4-trifluoromethoxyphenyloxy)methane

Difluoro-4-(trans-4-butylcyclohexyl)phenyl!-(3-fluoro-4-trifluoromethoxyphenyloxy)methane

Difluoro-4-(trans-4-pentylcyclohexyl)phenyl!-(3-fluoro-4-trifluoromethoxyphenyloxy)methane

Cr 35.9-36.3 N 61.1-61.3 Iso

COMPOUND PREPARATION EXAMPLE 2!

Preparation of difluoro-{4-2-(trans-4-propyl-cyclohexyl)ethyl!phenyl}-(3,4,5-trifluorophenyloxy)methane(An analogue of the compound of formula (I-1-7))

In a 500 ml three neck distillation flask provided with a stirrer,thermometer, dropping funnel, and nitrogen gas introducing pipe, 15.0 g(54.7 mmol) of 4- 2-(trans-4-propyl-cyclohexyl)ethyl!benzoic acid, 13.5g (65.6 mmol) of DCC, and 0.25 g (1.9 mmol) of DMAP were dissolved in250 ml of dichloromethane under nitrogen gas atmosphere, and then 9.7 g(65.6 mmol) of 3,4,5-trifluorophenol was added dropwise to the solutionin 3 min while stirring at room temperature. After the dropping, thesolution was stirred for 15 hours at room temperature. Then, 100 ml ofwater was added to the reaction solution. After dichloromethaneinsoluble matter was filtered off, the dichloromethane layer wasseparated and the water layer was further extracted with 200 ml ofdichloromethane. Extracted layers were mixed and washed with 100 ml×2 ofwater, 100 ml of saturated aqueous solution of sodium hydrogencarbonate,and 100 ml×2 of water in turn, dried over anhydrous magnesium sulfate,and then concentrated under a reduced pressure to obtain 22.5 g ofreaction product. Reaction product was purified by a columnchromatography using silica gel as filler and using toluene asdeveloping solvent, and further recrystallized from a mixed solvent ofheptane-ethanol to obtain 12.9 g of colorless crystal product. Thisproduct was 3,4,5-trifluoro-{4-2-(trans-4-propylcyclohexyl)ethyl!phenyl} benzoate.

Subsequently, in a 1000 ml egg-plant type flask provided with a nitrogengas introducing pipe and cooling pipe, 12.9 g (31.9 mmol) of3,4,5-trifluoro-{4- 2-(trans-4-propyl-cyclohexyl)ethyl!phenyl} benzoateobtained by the procedures mentioned above and 25.8 g (63.9 mmol) ofLawesson reagent were dissolved in 500 ml of toluene, and the solutionwas refluxed while stirring under nitrogen gas stream for 65 hours.After the reaction solution was cooled down to room temperature, 200 mlof water was added, the toluene layer was separated, and then the waterlayer was further extracted with 150 ml of toluene. Organic layers weremixed, washed with 200 ml×2 of water, 100 ml of saturated aqueoussolution of sodium hydrogencarbonate, 100 ml of 10% aqueous solution ofsodium hydrogensulfite, and 200×2 ml of water in turn, dried overanhydrous magnesium sulfate, and then concentrated under a reducedpressure to obtain 13.3 g of brown crystalline mixture. Reaction productwas purified by a column chromatography using silica gel as filler andusing heptane as developing solvent, and then recrystallized fromheptane to obtain 4.5 g of yellow needle-like crystal product. Thisproduct was 4- 2-(trans-4-propyl-cyclohexyl)ethyl!phenyl carbothioacid-O-3,4,5-trifluorophenyl.

Cr 95.5-97.6 Iso

1H-NMR (CDC13; δ ppm) 0.7-1.9(19H,m), 2.70(2H,m), 6.80(2H,m),7.25(2H,d,J=8.3 Hz), and 8.21(2H,d,J=8.3 Hz).

Subsequently, in a 100 ml egg-plant type flask provided with a nitrogengas introducing pipe, 4.5 g (10.8 mmol) of 4-2-(trans-4-propylcyclohexyl)ethyl!phenyl carbothioacid-O-3,4,5-trifluorophenyl was dissolved in 50 ml of dichloromethaneat room temperature, and then 5.3 g (32.6 mmol) of DAST was added to thesolution and then the solution was stirred at room temperature for 40hours. Reaction solution was added with 50 ml of water, thedichloromethane layer was separated, and the water layer was furtherextracted with 50 ml of dichloromethane. Extracted layers were mixed,washed with 50 ml×2 of water, 30 ml of saturated aqueous solution ofsodium hydrogencarbonate, and 50 ml×2 of water in turn, dried overanhydrous magnesium sulfate, and then concentrated under a reducedpressure to obtain 3.9 g of colorless crystal product. Reaction productwas purified by a column chromatography using silica gel as filler andusing heptane as developing solvent, and then recrystallized fromheptane to obtain 1.5 g of colorless needle-like crystal product. Thisproduct was difluoro-{4-2-(trans-4-propyl-cyclohexyl)ethyl!phenyl}-(3,4,5-trifluorophenyloxy)methane.

Cr 36.8-37.5 (NI 23.5-23.7) Iso

1H-NMR (CDC13; δ ppm) 0.7-2.0(19H,m), 2.68(2H,m), 6.93(2H,m),7.27(2H,d,J=8.4 Hz), and 7.58(2H,d,J=8.4 Hz).

Following compounds of formula (I-1) can be prepared according to thepreparation method mentioned above by using 4-2-(trans-4-alkylcyclohexyl)ethyl!benzoic acids having a different alkylchain in place of 4- 2-(trans-4-propylcycohexyl) ethyl!benzoic acid andusing several known phenol derivatives in place of3,4,5-trifluorophenol:

Difluoro-{4-2-(trans-4-ethylcyclohexyl)ethyl!phenyl}-(4-trifluoromethoxyphenyloxy)methane

Difluoro-{4-2-(trans-4-propylcyclohexyl)ethyl!phenyl}-(4-trifluoromethoxyphenyloxy)methane

Cr 60.2-60.9 N 72.6-73.2 Iso

Difluoro-{4-2-(trans-4-butylcyclohexyl)ethyl!phenyl}-(4-trifluoromethoxyphenyloxy)methane

Difluoro-{4-2-(trans-4-pentylcyclohexyl)ethyl!phenyl}-(4-trifluoromethoxyphenyloxy)methane

Difluoro-{4-2-(trans-4-ethylcyclohexyl)ethyl!phenyl}-(4-fluorophenyloxy)methane

Difluoro-{4-2-(trans-4-propylcyclohexyl)ethyl!phenyl}-(4-fluorophenyloxy)methane

Difluoro-{4-2-(trans-4-butylcyclohexyl)ethyl!phenyl}-(4-fluorophenyloxy)methane

Difluoro-{4-2-(trans-4-pentylcyclohexyl)ethyl!phenyl}-(4-fluorophenyloxy)methane

Difluoro-{4-2-(trans-4-ethylcyclohexyl)ethyl!phenyl}-(3,4-difluorophenyloxy)methane

Difluoro-{4-2-(trans-4-propylcyclohexyl)ethyl!phenyl}-(3,4-difluorophenyloxy)methane

Difluoro-{4-2-(trans-4-butylcyclohexyl)ethyl!phenyl}-(3,4-difluorophenyloxy)methane

Difluoro-{4-2-(trans-4-pentylcyclohexyl)ethyl!phenyl}-(3,4-difluorophenyloxy)methane

Difluoro-{4-2-(trans-4-ethylcyclohexyl)ethyl!phenyl}-(3-fluoro-4-trifluoromethoxyphenyloxy)methane

Difluoro-{4-2-(trans-4-propylcyclohexyl)ethyl!phenyl}-(3-fluoro-4-trifluoromethoxyphenyloxy)methane

Cr 30.8-31.3 N 76.9-77.7 Iso

Difluoro-{4-2-(trans-4-butylcyclohexyl)ethyl!phenyl}-(3-fluoro-4-trifluoromethoxyphenyloxy)methane

Difluoro-{4-2-(trans-4-pentylcyclohexyl)ethyl!phenyl}-(3-fluoro-4-trifluoromethoxyphenyloxy)methane

COMPOUND PREPARATION EXAMPLE 3!

Preparation of difluoro-(3',4',5'-trifluorobiphenyloxy)-4-(trans-4-propylcyclohexyl)phenyl!methane (An analogue of the compoundof formula (I-2-3))

1) Preparation of 4-(3,4,5-trifluorophenyl)phenol

By the following procedures, 4-(3,4,5-trifulorophenyl)phenol wasprepared which was a raw material for the preparation of the subjectcompound of the present Example. That is, in a 1000 ml three neckdistillation flask provided with a stirrer, thermometer, nitrogen gasintroducing pipe, dropping funnel, and cooling pipe, 7.9 g (324.2 mmol)of shavings of magnesium was added, and then a solution of 65.2 g (308.8mmol) of 3,4,5-trifluorobromobenzene in 80 ml of tetrahydrofuran(hereinafter abbreviated as THF) was added dropwise in 50 min so thatthe internal temperature was maintained at 50° C. After completion ofthe dropping, the solution was stirred on a hot water bath while keepingthe same temperature for 1 hour for ageing to prepare a Grignardreagent. Then, in a 1000 ml three neck distillation flack provided witha stirrer, thermometer, nitrogen gas introducing pipe, dropping funnel,and cooling pipe, separately provided for, 35.0 g (171.6 mmol) ofiodobenzene, 1.64 g ((9.3 mmol) of palladium chloride, and 300 ml of THFwere added under nitrogen gas atmosphere, and added dropwise with theGrignard reagent prepared by the procedures mentioned above in 50 minwhile refluxing. After the dropping, the solution was further refluxedfor 3 hours, cooled down to room temperature, and then added with 200 mlof water to terminate the reaction. After insoluble matter was filteredoff the solution, the solution was extracted with 300 ml×2 of toluene.Extracted layer was washed with 300 ml×3 of water, dried over anhydrousmagnesium sulfate, and concentrated under a reduced pressure to obtain38.4 g of dark brown solid. Concentrated residue was purified by achromatography using silica gel as filler and using heptane asdeveloping solvent, and then recrystallized from a mixed solvent ofheptane-ethanol to obtain 19.0 g of colorless crystal product. Thisproduct was 3,4,5-trifluorobiphenyl.

Subsequently, the biphenyl derivative thus obtained was subjected to abromination. That is, in a 100 ml three neck distillation flack providedwith a stirrer, thermometer, nitrogen gas introducing pipe, and droppingfunnel, 19.0 g (91.5 mmol) of the 3,4,5-trifluorobiphenyl prepared bythe procedure mentioned above was dissolved in 200 ml ofdichloromethane, cooled down to -5° C. while stirring, added with 0.26 g(4.6 mmol) of iron powder, and then added dropwise with 8.8 g (109.8mmol) of bromine in 15 min so that the temperature of -5 to 0° C. wasmaintained. After completion of the dropping, the solution was furtherstirred for 1 hour while maintaining the same temperature. Reactionsolution was added with 200 ml of water to terminate the reaction, andthen extracted with 250 ml×2 of toluene. Extracted layer was washed with200 ml× of 4 water, dried over anhydrous magnesium sulfate, andconcentrated under a reduced pressure to obtain 25.1 g of brown oilyproduct. Concentrated residue was purified by chromatography usingsilica gel as filler and using heptane as developing solvent, andrecrystallized from a mixed solvent of heptane-ethanol to obtain 16.6 gcolorless crystal product. This product was4-bromo-3',4',5'-trifluorobiphenyl.

With reference to the report by R. L. Kidwell et al. (Org. Synth., V,918 (1973)), the bromobiphenyl derivative obtained by the proceduresmentioned above was led to a phenylphenol derivative by the followingprocedures. That is, in a 300 ml three neck distillation flask providedwith a stirrer, thermometer, nitrogen gas introducing pipe, and droppingfunnel, 1.5 g (60.9 mmol) of shavings of magnesium was added, and asolution of 16.6 g (58.0 mmol) of 4-bromo-3',4',5'-trifluoro-biphenyl in30 ml of THF was added dropwise in 25 min so that the internaltemperature was maintained at 50° C. After completion of the dropping,the solution was stirred on a hot water bath for 1 hour while keepingthe same temperature for ageing to prepare a Grignard reagent. Then, thereaction solution was cooled with dry ice-acetone coolant down to -20°C., added dropwise with 7.2 g of trimethyl borate, and stirred at thesame temperature for 30 min. The solution was added with 3.5 g (58.0mmol) of acetic acid at the same temperature, raised up to 20° C., andadded dropwise with 7.9 g (69.6 mmol) of 30% aqueous solution ofhydrogen peroxide in 10 min so that temperature of 25° C. wasmaintained. Reaction solution was again cooled with the coolant down to-30° C. and added dropwise with 50 ml of 20% aqueous solution of sodiumthiosulfate in 10 min to terminate the reaction. Reaction solution wasextracted with 150 ml×3 of ethyl acetate, washed with 200 ml×2 ofsaturated brine, dried over magnesium sulfate, and then concentratedunder a reduced pressure to obtain 14.5 g of brown solid product.Concentrated residue was recrystallized from a mixed solvent ofheptane-toluene to obtain 10.9 g of colorless crystal product. Thisproduct was 4-(3,4,5-trifluorophenyl) phenol.

2) Preparation of difluoro-(3',4',5'-trifluorobiphenyloxy)-4-(trans-4-propylcyclohexyl)phenyl!methane

In a 500 ml three neck distillation flask provided with a stirrer,thermometer, dropping funnel, and nitrogen gas introducing pipe, 15.0 g(60.9 mmol) of 4-(trans-4-propyl-cyclohexyl)benzoic acid, 15.1 g (73.1mmol) of DCC, and 0.27 g (2.2 mmol) of DMAP were dissolved in 300 ml ofdichloromethane, and then a solution of 16.4 g (73.1 mmol) of the4-(3,4,5-trifluorophenyl)phenol mentioned above in 80 ml ofdichloromethane was added dropwise at room temperature in 20 min whilestirring. After the dropping, the solution was stirred at roomtemperature for 10 hours. After the reaction solution was added with 200ml of water, the dichloromethane insoluble matter was filtered off, thedichloromethane layer was separated, and the water layer was furtherextracted with 200 ml of dichoromethane. Extracted layers were mixed,washed with 200 ml ×2 of water, 100 ml of saturated aqueous solution ofsodium hydrogencarbonate, and 200 ml×2 of water in turn, dried overanhydrous magnesium sulfate, and then concentrated under a reducedpressure to obtain 26.9 g of reaction product. The reaction product waspurified by a chromatography using silica gel as filler and usingtoluene as developing solvent, and further recrystallized from a mixedsolvent of heptane-ethanol to obtain 22.8 g of colorless crystalproduct. This product was(3',4',5'-trifluorobiphenyl)-4-(trans-4-cyclohexyl)benzoate.

Subsequently, in a 1000 ml egg-plant type flask provided with a nitrogengas introducing pipe and cooling pipe, 22.8 g (50.5 mmol) of(3',4',5'-trifluorobiphenyl)-4-(trans-4-cyclo-hexyl)benzoate obtained bythe procedures mentioned above and 40.9 g (101.1 mmol) of Lawessonreagent were dissolved in 500 ml of toluene, and the solution wasrefluxed while stirring under nitrogen gas stream for 60 hours. Afterthe reaction solution was cooled down to room temperature, 200 ml ofwater was added, the toluene layer was separated, and then the waterlayer was further extracted with 200 ml of toluene. Organic layers weremixed, washed with 200 ml×2 of water, 100 ml of saturated aqueoussolution of sodium hydrogencarbonate, 100 ml of 10% aqueous solution ofsodium hydrogensulfite, and 200 ml×2 of water in turn, dried overanhydrous magnesium sulfate, and then concentrated under a reducedpressure to obtain 23.4 g of brown crystalline mixture. Reaction productwas purified by a column chromatography using silica gel as filler andusing heptane as developing solvent, and then recrystallized fromheptane to obtain 8.3 g of yellow needle-like crystal product. Thisproduct was 4-(trans-4-propylcyclohexyl)phenyl carbothioacid-O-3',4',5'-trifluorobiphenyl.

In a 100 ml egg-plant type flask provided with a nitrogen gasintroducing pipe, 8.3 g (17.7 mmol) of4-(trans-4-propyl-cyclohexyl)phenyl carbothioacid-O-3',4',5'-trifluorobiphenyl was dissolved in 80 ml ofdichloromethane at room temperature, and then 8.5 g (53.0 mmol) of DASTwas added to the solution and the solution was stirred at roomtemperature for 40 hours. Reaction solution was added with 50 ml ofwater, the dichloromethane layer was separated, and the water layer wasfurther extracted with 50 ml of dichloromethane. Extracted layers weremixed, washed with 50 ml×2 of water, 30 ml of saturated aqueous solutionof sodium hydrogencarbonate, and 50 ml×2 of water in turn, dried overanhydrous magnesium sulfate, and then concentrated under a reducedpressure to obtain 8.1 g of brown crystal product. Reaction product waspurified by a column chromatography using silica gel as filler and usingheptane as developing solvent, and then recrystallized from heptane toobtain 1.9 g of colorless needle-like crystal product. This product wasdifluoro-(3',4',5'-trifluoro-biphenyloxy)-4-(trans-4-propylcyclohexyl)phenyl!methane.

Following compounds of formula (I-2) can be prepared according to thepreparation method mentioned above by using several known benzoic acidderivatives and several known phenol derivatives in place of4-(trans-4-propylcyclohexyl)benzoic acid and 3',4',5'-trifluorobiphenol:

Difluoro-(4'-trifluoromethoxybiphenyloxy)-4-(trans-4-ethylcyclohexyl)phenyl!methane

Difluoro-(4'-trifluoromethoxybiphenyloxy)-4-(trans-4-propylcyclohexyl)phenyl!methane

Difluoro-(4'-trifluoromethoxybiphenyloxy)-4-(trans-4-butylcyclohexyl)phenyl!methane

Difluoro-(4'-trifluoromethoxybiphenyloxy)-4-(trans-4-pentylcyclohexyl)phenyl!methane

Difluoro-(3',4'-difluorobiphenyloxy)-4-(trans-4-ethyl-cyclohexyl)phenyl!methane

Difluoro-(3',4'-difluorobiphenyloxy)-4-(trans-4-propyl-cyclohexyl)phenyl!methane

Difluoro-(3',4'-difluorobiphenyloxy)-4-(trans-4-butyl-cyclohexyl)phenyl!methane

Difluoro-(3',4'-difluorobiphenyloxy)-4-(trans-4-pentyl-cyclohexyl)phenyl!methane

Difluoro-(3'-fluoro-4'-trifluoromethoxybiphenyloxy)-4-(trans-4-ethylcyclohexyl)phenyl!methane

Difluoro-(3'-fluoro-4'-trifluoromethoxybiphenyloxy)-4-(trans-4-propylcyclohexyl)phenyl!methane

Difluoro-(3'-fluoro-4'-trifluoromethoxybiphenyloxy)-4-(trans-4-butylcyclohexyl)phenyl!methane

Difluoro-(3'-fluoro-4'-trifluoromethoxybiphenyloxy)-4-(trans-4-pentylcyclohexyl)phenyl!methane

Difluoro-(4'-trifluoromethoxybiphenyloxy)-{4-2-(trans-4-ethylcyclohexyl)ethyl!phenyl}methane

Difluoro-(4'-trifluoromethoxybiphenyloxy)-{4-2-(trans-4-propylcyclohexyl)ethyl!phenyl}methane

Difluoro-(4'-trifluoromethoxybiphenyloxy)-{4-2-(trans-4-butylcyclohexyl)ethyl!phenyl}methane

Difluoro-(4'-trifluoromethoxybiphenyloxy)-{4-2-(trans-4-pentylcyclohexyl)ethyl!phenyl}methane

Next, Examples and Comparative Examples of the liquid crystalcompositions of the present invention are described. In the Examples andComparative Examples, every ratio of the compound in the compositionsare shown by "% by weight". Further, the compounds used in the Examplesand Comparative Examples are designated by symbols based on thedefinition shown in Table 1.

                                      TABLE 1                                     __________________________________________________________________________    Method for Designating Compounds Using Symbols R(A.sub.1)Z.sub.1 . . .        Z.sub.n(A.sub.n)X                                                             __________________________________________________________________________    1) Left side terminal                3) Bonding group                         group R                     Symbol   Z.sub.1, Z.sub.n                                                                             Symbol                    __________________________________________________________________________    C.sub.n H.sub.2n+1          n-       CH.sub.2 CH.sub.2                                                                            2                         C.sub.n H.sub.2n+1 O        nO       COO            E                         C.sub.n H.sub.2n+1 OC.sub.m H.sub.2m                                                                      nOm-     C C            T                         CH.sub.2CHC.sub.n H.sub.2n  Vn-      CHCH           V                         C.sub.n H.sub.2n+1 CHCHC.sub.m H.sub.2m                                                                   nVm-     CF.sub.2 O     CF2O                      C.sub.n H.sub.2n+1 CHCHC.sub.m H.sub.2m CHCHC.sub.k H.sub.2k                                              nVmvk-                                            __________________________________________________________________________    2) Ring structure                    4) Right side terminal                   (A.sub.1), (A.sub.n)        Symbol   group X        Symbol                    __________________________________________________________________________     ##STR18##                  B        F              F                          ##STR19##                  B(F)     Cl             CL                         ##STR20##                  B(F,F)   CN             C                          ##STR21##                  H        CF.sub.3       CF3                        ##STR22##                  Py       OCF.sub.3      OCF3                       ##STR23##                  D        OCF.sub.2 H    OCF2H                      ##STR24##                  Ch       C.sub.n H.sub.2n+1                                                            OC.sub.n H.sub.2n+1                                                                          On                                                             COOCH.sub.3    EMe                       __________________________________________________________________________    5) Examples of symbol                                                         __________________________________________________________________________    Ex. 1                           Ex. 3                                         3-H2B(F,F)B(F)F                 IV2-BEB(F,F)C                                  ##STR25##                                                                                                     ##STR26##                                    Ex. 2                                                                         3-HB(F)TB-2                                                                    ##STR27##                                                                    __________________________________________________________________________

Data on the characteristics of liquid crystal compositions are shown byclearing point (TNI), smectic-nematic phase transition point (TSN) ,viscosity at 20° C. (η20), optical anisotropy at 25° C. (Δn), dielectricanisotropy at 25° C. (Δε), and threshold voltage at 20° C. (Vth).

Voltage holding ratio was determined based on "Area Method" (methodreported in Tatsuo Shimasaki et al., "Voltage Holding Characteristics Iof TFT-LCD", Abstracts of Presentation for 14th Seminar on LiquidCrystals, p 78 (1988)), and actual determination was carried out at 25°C. at a frame period of 60 Hz, voltage of 5.0 volt, and ON time of 60μsec; using a liquid crystal cell in which thickness of liquid crystallayer was 7.0 μm and a polyimide type alignment film was formed by arubbing method on a substrate on which an ITO pattern having anelectrode area of 1 cm² was evaporated.

TSN point was judged by liquid crystal phases after liquid crystalcompositions were left in each of freezers at 0° C., -10° C., -20° C.,and -30° C., respectively, for 30 days.

COMPARATIVE EXAMPLE 1

Following composition disclosed in Application Example 2 of JapanesePatent Application Laid-open No. Hei 2-233626 was prepared:

    ______________________________________                                               3-HHB(F,F)-F                                                                           15.0%                                                                2-HHB(F)-F                                                                             28.4%                                                                3-HHB(F)-F                                                                             28.3%                                                                5-HHB(F)-F                                                                             28.3%                                                         ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=110.7° C.

TSN<0° C.

η20=25.0 mPa·s

Δn=0.077

Vth=2.32 (V)

V.H.R.=98.8%

This liquid crystal composition had a large threshold voltage and waspoor in miscibility at low temperatures (TSN was high). Also, thiscomposition was slightly small in Δn. Thus, this composition wasinsufficient in practicability.

COMPARATIVE EXAMPLE 2

Following composition disclosed in Example 1 of WO 94/03558 wasprepared:

    ______________________________________                                               7-HB(F,F)-F                                                                            10.0%                                                                2-HHB(F,F)-F                                                                           25.0%                                                                3-HHB(F,F)-F                                                                           35.0%                                                                5-HHB(F,F)-F                                                                           18.0%                                                                7-HB(F)-F                                                                              12.0%                                                         ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=42.9° C.

TSN<0° C.

η20=22.2 mPa·s

Δn=0.059

Vth=1.07 (V)

V.H.R.=98.7%

Whereas this liquid crystal composition had a law threshold voltage, itwas low in clearing point and poor in miscibility at low temperatures.Besides, this composition was small in Δn. Thus, the composition isinsufficient in practicability.

Comparative Example 3

Following composition disclosed in Example 2 of WO 94/03558 wasprepared:

    ______________________________________                                               2-HHB(F,F)-F                                                                           26.0%                                                                3-HHB(F,F)-F                                                                           26.0%                                                                5-HHB(F,F)-F                                                                           26.0%                                                                7-HB(F)-F                                                                              12.0%                                                                5-H2B(F)-F                                                                             10.0%                                                         ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=46.0° C.

TSN<0° C.

η20=21.6 mPa·s

Δn=0.058

Vth=1.17 (V)

V.H.R.=98.5%

Whereas this liquid crystal composition had a law threshold voltage, itwas low in clearing point and poor in miscibility at low temperatures.Besides, this composition was small in Δn. Thus, the composition isinsufficient in practicability.

EXAMPLE 1

    ______________________________________                                        5-HBCF2OB-F       10%                                                         5-HBCF2OB(F)-OCF3 15%                                                         2-HHB(F)-F        10%                                                         3-HHB(F)-F        10%                                                         5-HHB(F)-F        10%                                                         2-H2HB(F)-F       10%                                                         3-H2HB(F)-F        5%                                                         5-H2HB(F)-F       10%                                                         2-HBB(F)-F         5%                                                         3-HBB(F)-F         5%                                                         5-HBB(F)-F        10%                                                         ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=87.9° C.

TSN<-30° C.

η20=24.1 mPa·s

Δn=0.094

Δε=5.9

Vth=2.02 (V)

V.H.R.=98.8%

This liquid crystal composition was excellent particularly inmiscibility at low temperatures compared to the compositions inComparative Examples 1 to 3 and had a high Δn. Also, the composition ofthis Example was low in viscosity and small in Vth for its high clearingpoint such an degree that it has no problems in practical use, comparedwith the composition of Comparative Example 1.

EXAMPLE 2

    ______________________________________                                        3-HBCF2OB(F)-OCF3 10%                                                         2-HHB(F)-F        10%                                                         3-HHB(F)-F        10%                                                         5-HHB(F)-F        10%                                                         2-H2HB(F)-F       8%                                                          3-H2HB(F)-F       4%                                                          5-H2HB(F)-F       8%                                                          3-HHB-C1          5%                                                          3-HHEB-F          4%                                                          5-HHEB-F          4%                                                          3-HBEB-F          4%                                                          1O1-HH-3          5%                                                          3-HH-5            5%                                                          1O1-HBBH-3        3%                                                          3-H2BB(F,F)-F     5%                                                          3-H2HB(F,F)-F     5%                                                          ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=110.5° C.

TSN<-20° C.

η20=24.2 mPa·s

Δn=0.081

Δε=4.7

Vth=2.29 (V)

V.H.R.=98.5%

This liquid crystal composition was excellent in miscibility at lowtemperatures and high in Δn, compared with the compositions ofComparative Examples 1 to 3. Also, the composition of this Example waslow in viscosity and small in Vth, compared with the composition ofComparative Example 1.

EXAMPLE 3

    ______________________________________                                        3-HBCF2OB-OCF3   5%                                                           7-HB(F)-F        10%                                                          2-HHB(F)-F       12%                                                          3-HHB(F)-F       12%                                                          5-HHB(F)-F       12%                                                          2-HBB(F)-F       5%                                                           3-HBB(F)-F       5%                                                           5-HBB(F)-F       10%                                                          3-HHB-F          5%                                                           3-HHEB(F,F)-F    10%                                                          3-HH2B(F,F)-F    8%                                                           2-HHHB(F,F)-F    3%                                                           3-HH2BB(F,F)-F   3%                                                           ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=92.2° C.

TSN<-30° C.

η20=24.3 mPa·s

Δn=0.091

Δε=6.1

Vth=1.97 (V)

V.H.R.=98.3%

This liquid crystal composition was excellent particularly inmiscibility at low temperatures and high in Δn compared with thecompositions of Comparative Examples 1 to 3. Also, the composition ofthis Example was low in viscosity and small in Vth for its high clearingpoint, compared with the composition of Comparative Example 1.

EXAMPLE 4

    ______________________________________                                        3-H2BCF2OB-OCF3   5%                                                          3-HBCF2OB-OCF3    15%                                                         2-HHB(F)-F        10%                                                         3-HHB(F)-F        10%                                                         5-HHB(F)-F        10%                                                         2-HBB(F)-F        4%                                                          3-HBB(F)-F        4%                                                          5-HBB-(F)-F       8%                                                          3-HH2B-OCF3       6%                                                          5-H2HB-OCF3       6%                                                          3-HB-O2           4%                                                          3-HHB-O1          4%                                                          3-HHB(F,F)-F      5%                                                          5-HHB(F,F)-F      3%                                                          5-HH2B(F,F)-F     6%                                                          ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=99.9° C.

TSN<-20° C.

η20=21.5 mPa·s

Δn=0.096

Δε=5.5

Vth=2.18 (V)

V.H.R.=99.9%

EXAMPLE 5

    ______________________________________                                        3-HBCF2OB-OCF3   5%                                                           5-HBCF2OB-OCF3   10%                                                          2-HHB-(F)-F      12%                                                          3-HHB(F)-F       12%                                                          5-HHB(F)-F       12%                                                          3-HHB-F          4%                                                           2-H2HB(F)-F      2%                                                           3-H2HB(F)-F      1%                                                           5-H2HB(F)-F      2%                                                           2-HBB(F)-F       4%                                                           3-HBB(F)-F       4%                                                           5-HBB(F)-F       8%                                                           2-HBB-F          3%                                                           3-HBB-F          3%                                                           5-HBB-F          2%                                                           7-HB(F)-F        4%                                                           5-H2B(F)-F       6%                                                           3-HHB-1          6%                                                           ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=87.9° C.

TSN<-20° C.

η20=20.5 mPa·s

Δn=0.095

Δε=5.0

Vth=2.22 (V)

V.H.R.=98.6%

EXAMPLE 6

The composition comprising the following compounds was prepared:

    ______________________________________                                        5-HBCF2OB-OCF3     5%                                                         3-H2BCF2OB-OCF3    5%                                                         3-H2BCF2OBB(F)-OCF3                                                                              5%                                                         2-HHB(F)-F         10%                                                        3-HHB(F)-F         10%                                                        5-HHB(F)-F         10%                                                        3-HHB-F            4%                                                         2-HBB(F)-F         4%                                                         3-HBB(F)-F         4%                                                         5-HBB(F)-F         8%                                                         2-HBB-F            3%                                                         3-HBB-F            3%                                                         5-HBB-F            3%                                                         2-H2BB(F)-F        4%                                                         3-H2BB(F)-F        4%                                                         5-H2BB(F)-F        4%                                                         7-HB(F)-F          3%                                                         5-H2B(F)-F         5%                                                         3-HHB-1            6%                                                         ______________________________________                                    

EXAMPLE 7

    ______________________________________                                        3-HBCF2OB-OCF3   10%                                                          2-HBB(F)-F       6%                                                           3-HBB(F)-F       6%                                                           5-HBB(F)-F       12%                                                          3-HB-Cl          5%                                                           5-HB-Cl          5%                                                           7-HB-Cl          5%                                                           2-HHB-Cl         6%                                                           3-HHB-Cl         7%                                                           5-HHB-Cl         6%                                                           3-HB(F)TB-2      3%                                                           3-HB(F)VB-2      3%                                                           3-HBB(F,F)-F     13%                                                          5-HBB(F,F)-F     13%                                                          ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=90.1° C.

TSN<-20° C.

η20=22.1 mPa·s

Δn=0.109

Δε=6.1

Vth=2.13 (V)

V.H.R.=98.8%

EXAMPLE 8

    ______________________________________                                        3-HBCF2OB-OCF3    15%                                                         5-HBCF2OB-OCF3    15%                                                         5-HBCF2OB(F)-OCF3 10%                                                         2-HHB(F)-F        8%                                                          3-HHB(F)-F        8%                                                          5-HHB(F)-F        8%                                                          3-HHB-F           3%                                                          2-H2HB(F)-F       4%                                                          3-H2HB(F)-F       2%                                                          5-H2HB(F)-F       4%                                                          3-HHEB-F          3%                                                          5-HHEB-F          3%                                                          3-HHB-1           3%                                                          3-HHB-O1          3%                                                          7-HB(F,F)-F       3%                                                          3-HHB(F,F)-F      4%                                                          4-HHB(F,F)-F      4%                                                          ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=90.8° C.

TSN<-20° C.

η20=21.6 mPa·s

Δn=0.085

Δε=6.2

Vth=2.04 (V)

V.H.R.=98.2%

EXAMPLE 9

    ______________________________________                                        5-HBCF2OB(F)-OCF3 10%                                                         2-HHB(F)-F        10%                                                         3-HHB(F)-F        10%                                                         5-HHB(F)-F        10%                                                         2-H2HB(F)-F       6%                                                          3-H2HB(F)-F       3%                                                          5-H2HB(F)-F       6%                                                          3-HHEB-F          3%                                                          5-HHEB-F          3%                                                          3-HBEB-F          3%                                                          7-HB(F)-F         5%                                                          3-HHB-Cl          4%                                                          3-HHB-1           4%                                                          3-HHB-O1          4%                                                          2-HHB(F,F)-F      5%                                                          3-HHB(F,F)-F      5%                                                          3-HHEB(F,F)-F     5%                                                          3-HBEB(F,F)-F     4%                                                          ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=104.9° C.

TSN<-30° C.

η20=26.1 mPa·s

Δn=0.084

Δε=6.3

Vth=2.07 (V)

V.H.R.=99.0%

EXAMPLE 10

    ______________________________________                                        5-HBCF2OB-OCF3   15%                                                          2-HHB(F)-F       10%                                                          3-HHB(F)-F       10%                                                          5-HHB(F)-F       10%                                                          2-H2HB(F)-F      6%                                                           3-H2HB(F)-F      3%                                                           5-H2HB(F)-F      6%                                                           2-HBB(F)-F       3%                                                           3-HBB(F)-F       3%                                                           5-HBB(F)-F       6%                                                           3-HHEB-F         4%                                                           5-HHEB-F         4%                                                           3-HHEBB-F        3%                                                           5-HHEBB-F        3%                                                           7-HB(F)-F        4%                                                           5-HB-F           5%                                                           6-HB-F           5%                                                           ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=89.6° C.

TSN<-20° C.

η20=21.8 mPa·s

Δn=0.087

Δε=5.1

Vth=2.15 (V)

V.H.R.=98.4%

EXAMPLE 11

    ______________________________________                                        5-HBCF2OB(F)-F   3%                                                           3-HBCF2OB-OCF3   5%                                                           5-HBCF2OB-OCF3   9%                                                           2-HHB(F)-F       11%                                                          3-HHB(F)-F       11%                                                          5-HHB(F)-F       11%                                                          3-HHB-F          5%                                                           2-HBB(F)-F       3%                                                           3-HBB(F)-F       3%                                                           5-HBB(F)-F       6%                                                           3-HHEBB-F        4%                                                           5-HHEBB-F        3%                                                           7-HB(F)-F        15%                                                          3-HB-O2          3%                                                           3-HHB-1          5%                                                           3-HHB-O1         3%                                                           ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=91.4° C.

TSN<-20° C.

η20=19.8 mPa·s

Δn=0.092

Δε=4.8

Vth=2.25 (V)

V.H.R.=98.7%

EXAMPLE 12

    ______________________________________                                        5-HBCF2OB(F)-F   6%                                                           2-HHB(F)-F       13%                                                          3-HHB(F)-F       13%                                                          5-HHB(F)-F       13%                                                          2-H2HB(F)-F      8%                                                           3-H2HB(F)-F      4%                                                           5-H2HB(F)-F      8%                                                           2-HBB(F)-F       5%                                                           3-HBB(F)-F       5%                                                           5-HBB(F)-F       10%                                                          7-HB(F)-F        8%                                                           5-H2B(F)-F       7%                                                           ______________________________________                                    

Physical properties of this liquid crystal composition are shown below:

TNI=70.4° C.

TSN<-30° C.

η20=20.9 mPa·s

Δn=0.081

Δε=4.8

Vth=1.96 (V)

V.H.R.=98.6%

EXAMPLE 13

The composition comprising the following compounds was prepared:

    ______________________________________                                        5-HBCF2OB-F      5%                                                           3-H2BCF2OB(F)-F  5%                                                           2-HHB(F)-F       10%                                                          3-HHB(F)-F       10%                                                          5-HHB(F)-F       10%                                                          2-H2HB(F)-F      6%                                                           3-H2HB(F)-F      3%                                                           5-H2HB(F)-F      6%                                                           3-HHEB-F         3%                                                           5-HHEB-F         3%                                                           3-HBEB-F         3%                                                           7-HB(F)-F        5%                                                           3-HHB-Cl         4%                                                           3-HHB-1          4%                                                           3-HHB-O1         4%                                                           2-HHB(F,F)-F     5%                                                           3-HHB(F,F)-F     5%                                                           3-HHEB(F,F)-F    5%                                                           3-HBEB(F,F)-F    4%                                                           ______________________________________                                    

EXAMPLE 14

The composition comprising the following compounds was prepared:

    ______________________________________                                        5-H2BCF2OB(F)-OCF3 9%                                                         3-HBCF2OBB-OCF3    3%                                                         5-HBCF2OBB(F)-F    3%                                                         2-HHB(F)-F         10%                                                        3-HHB(F)-F         10%                                                        5-HHB(F)-F         10%                                                        2-H2HB(F)-F        6%                                                         3-H2HB(F)-F        3%                                                         5-H2HB(F)-F        6%                                                         2-HBB(F)-F         3%                                                         3-HBB(F)-F         3%                                                         5-HBB(F)-F         6%                                                         3-HHEB-F           4%                                                         5-HHEB-F           4%                                                         3-HHEBB-F          3%                                                         5-HHEBB-F          3%                                                         7-HB(F)-F          4%                                                         5-HB-F             5%                                                         6-HB-F             5%                                                         ______________________________________                                    

EXAMPLE 15

The composition comprising the following compounds was prepared:

    ______________________________________                                        5-HBCF2OB(F)-F    4%                                                          3-HBCF2OB-OCF3    5%                                                          3-H2BCF2OBB-F     4%                                                          5-H2BCF2OBB(F)-F  4%                                                          2-HHB(F)-F        11%                                                         3-HHB(F)-F        11%                                                         5-HHB(F)-F        11%                                                         3-HHB-F           5%                                                          2-HBB(F)-F        3%                                                          3-HBB(F)-F        3%                                                          5-HBB(F)-F        6%                                                          3-HHEBB-F         4%                                                          5-HHEBB-F         3%                                                          7-HB(F)-F         15%                                                         3-HB-O2           3%                                                          3-HHB-1           5%                                                          3-HHB-O1          3%                                                          ______________________________________                                    

EXAMPLE 16

The composition comprising the following compounds was prepared:

    ______________________________________                                        5-H2BCF2OBB-OCF3  5%                                                          2-HHB(F)-F        13%                                                         3-HHB(F)-F        13%                                                         5-HHB(F)-F        13%                                                         2-H2HB(F)-F       8%                                                          3-H2HB(F)-F       4%                                                          5-H2HB(F)-F       8%                                                          2-HBB(F)-F        5%                                                          3-HBB(F)-F        5%                                                          5-HBB(F)-F        10%                                                         7-HB(F)-F         8%                                                          5-H2B(F)-F        8%                                                          ______________________________________                                    

EXAMPLE 17

The composition comprising the following compounds was prepared:

    ______________________________________                                        5-HBCF2OB(F)-F     16%                                                        5-HBCF2OBB-F        3%                                                        3-HBCF2OBB(F)-OCF3  3%                                                        3-H2BCF2OBB-OCF3    3%                                                        2-HHB(F)-F         10%                                                        3-HHB(F)-F         10%                                                        5-HHB(F)-F         10%                                                        2-H2HB(F)-F        10%                                                        3-H2HB(F)-F         5%                                                        5-H2HB(F)-F        10%                                                        2-HBB(F)-F          5%                                                        3-HBB(F)-F          5%                                                        5-HBB(F)-F         10%                                                        ______________________________________                                    

EXAMPLE 18

The composition comprising the following compounds was prepared:

    ______________________________________                                        3-H2BCF2OB-OCF3   4%                                                          3-H2BCF2OBB-OCF3  3%                                                          5-HB-F            9%                                                          6-HB-F            9%                                                          7-HB-F            9%                                                          3-HBB(F)-F        11%                                                         5-HBB(F)-F        11%                                                         2-HHB-OCF3        8%                                                          3-HHB-OCF3        8%                                                          4-HHB-OCF3        8%                                                          5-HHB-OCF3        8%                                                          3-HH2B-OCF3       4%                                                          5-HH2B-OCF3       4%                                                          3-HBBH-5          2%                                                          3-HB(F)BH-3       2%                                                          ______________________________________                                    

EXAMPLE 19

The composition comprising the following compounds was prepared:

    ______________________________________                                        3-HBCF2OB-OCF3   10%                                                          5-HBCF2OB-OCF3   9%                                                           5-HB-F           6%                                                           7-HB-F           6%                                                           3-HH-O1          3%                                                           3-HHB-OCF3       5%                                                           5-HHB-OCF3       5%                                                           3-HH2B-F         8%                                                           5-HH2B-F         8%                                                           3-HH2B(F)-F      8%                                                           5-HH2B(F)-F      8%                                                           3-HBB(F)-F       12%                                                          5-HBB(F)-F       12%                                                          ______________________________________                                    

According to the present invention, liquid crystal compositions areprovided which are excellent particularly in the miscibility at lowtemperatures, properly high in Δn, and small in the Vth and viscosity,while satisfying several characteristics required of liquid crystalcompositions for AM-LCD.

INDUSTRIAL APPLICABILITY

Liquid crystal compositions of the present invention are useful asliquid crystal material for low voltage in several modes such as activematrix mode and STN mode.

We claim:
 1. A liquid crystal composition containing, as a firstcomponent, at least one compound expressed by general formula either(I-1) or (I-2), and containing, as a second component, at least onecompound expressed by any one of general formulas (Il-1) to (II-7)##STR28## wherein n is an integer of 1 to 10, Z¹ represents --CH₂ CH₂ --or single bond, X represents F or OCF₃, Y represents H or F, and m is 0or
 1. 2. The liquid crystal composition according to claim 1 wherein theamount of the first component is 3 to 40% by weight and the amount ofthe second component is 60 to 97% by weight based on the total weight ofthe liquid crystal composition, respectively.
 3. The liquid crystalcomposition according to claim 1 or 2 wherein the liquid crystalcomposition further contains a compound expressed by general formula(III) ##STR29## wherein n is an integer of 1 to 10, X represents F orOCF₃, Y represents F or H, and Z² represents --CH₂ CH₂ --or single bond.4. The liquid crystal composition according to claim 1 or 2 wherein theliquid crystal composition further contains a compound expressed bygeneral formula (IV-1) and/or general formula (IV-2) ##STR30## wherein nis an integer of 1 to
 10. 5. The liquid crystal composition according toclaim 1 or 2 wherein the liquid crystal composition further contains atleast one compound expressed by any one of general formulas (V-1) to(V-3) ##STR31## wherein R¹, R³, and R⁵ represent an alkyl group oralkenyl group having 1 to 10 carbon atoms, in any of R¹, R³, and R⁵, anyone or not adjacent two methylene (--CH₂ --) group may be replaced byoxygen (--O--) atom, R², R⁴, and R⁶ represent an alkyl group or alkoxygroup having 1 to 10 carbon atoms, A represents trans-4-cyclohexylenegroup or 1,4-phenylene group, Z³ represents --CH═CH-- or --C.tbd.C--, Yrepresent H or F, and p is 0 or
 1. 6. A liquid crystal display devicecomprising a liquid crystal composition defined in claim 1 or
 2. 7. Theliquid crystal composition according to claim 3 wherein the liquidcrystal composition further contains a compound expressed by generalformula (IV-1) and/or general formula (IV-2) ##STR32## wherein n is aninteger of 1 to
 10. 8. The liquid crystal composition according to claim3 wherein the liquid crystal composition further contains at least onecompound expressed by any one of general formulas (V-1) to (V-3)##STR33## wherein R¹, R³, and R⁵ represent an alkyl group or alkenylgroup having 1 to 10 carbon atoms, in any of R¹, R³, and R⁵, any one ornot adjacent two methylene (--CH₂ --) group may be replaced by oxygen(--O--) atom, R², R⁴, and R⁶ represent an alkyl group or alkoxy grouphaving 1 to 10 carbon atoms, A represents trans-4-cyclohexylene group or1,4-phenylene group, Z³ represents --CH═CH-- or --C.tbd.C--, Y representH or F, and p is 0 or
 1. 9. The liquid crystal composition according toclaim 4 wherein the liquid crystal composition further contains at leastone compound expressed by any one of general formulas (V-1) to (V-3)##STR34## wherein R¹, R³, and R⁵ represent an alkyl group or alkenylgroup having 1 to 10 carbon atoms, in any of R¹, R³, and R⁵, any one ornot adjacent two methylene (--CH₂ --) group may be replaced by oxygen(--O--) atom, R², R⁴, and R⁶ represent an alkyl group or alkoxy grouphaving 1 to 10 carbon atoms, A represents trans-4-cyclohexylene group or1,4-phenylene group, Z³ represents --CH═CH-- or --C.tbd.C--, Y representH or F, and p is 0 or
 1. 10. The liquid crystal composition according toclaim 7 wherein the liquid crystal composition further contains at leastone compound expressed by any one of general formulas (V-1) to (V-3)##STR35## wherein R¹, R³, and R⁵ represent an alkyl group or alkenylgroup having 1 to 10 carbon atoms, in any of R¹, R³, and R⁵, any one ornot adjacent two methylene (--CH₂ --) group may be replaced by oxygen(--O--) atom, R², R⁴, and R⁶ represent an alkyl group or alkoxy grouphaving 1 to 10 carbon atoms, A represents trans-4-cyclohexylene group or1,4-phenylene group, Z³ represents --CH═CH-- or --C.tbd.C--, Y representH or F, and p is 0 or
 1. 11. A liquid crystal display device comprisinga liquid crystal composition defined in claim
 3. 12. A liquid crystaldisplay device comprising a liquid crystal composition defined in claim4.
 13. A liquid crystal display device comprising a liquid crystalcomposition defined in claim
 5. 14. A liquid crystal display devicecomprising a liquid crystal composition defined in claim
 7. 15. A liquidcrystal display device comprising a liquid crystal composition definedin claim
 8. 16. A liquid crystal display device comprising a liquidcrystal composition defined in claim
 9. 17. A liquid crystal displaydevice comprising a liquid crystal composition defined in claim 10.